Confused about LOCL vs. other features

So I have just made my first locl feature (to substitute steeper acutes for Polish) and am very happy this works. However, when I select Polish as a paragraph's language in InDesign, this is also the only OT feature that works. All my existing –language UNspecific– features only work when I select any language but Polish (or Hungarian, which also has a language specific feature). I can't even select a different figure style! I mean I can select it, but it doesn't work. It seems like the language thing obliterates/overrides all other options.

What's the deal – am I supposed to specify in the "general" features that they are for any language, and not just the DFLT?
(Apologies – this does feel like it's probably a rather stupid question…)

Sometimes I think there's too much to ever get my head round. Mental note to return to this useful thread when I understand a bit more about Opentype. Who would've thought there's so many possibilities?!